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InFocus: Treating Extensor Tendon Injuries in the ED

Roberts, James R. MD

doi: 10.1097/01.EEM.0000410878.95948.d1
InFocus
It is almost impossible to sustain a laceration in this area and avoid at least some injury to the superficial extensor tendon apparatus or joint capsule. Function may not be compromised even with a significant tendon defect so one has to explore the laceration carefully. Note the sterile glove, tourniquet, good lighting, and visual inspection.

It is almost impossible to sustain a laceration in this area and avoid at least some injury to the superficial extensor tendon apparatus or joint capsule. Function may not be compromised even with a significant tendon defect so one has to explore the laceration carefully. Note the sterile glove, tourniquet, good lighting, and visual inspection.

An extensor tendon injury is a major threat to hand function, and should not be taken lightly. Compared with flexor tendons, extensor tendon injuries are more common and less complex, and these minor partial lacerations are more forgiving of primary repair in the ED. Repair of complete tendon lacerations should be referred to a hand surgeon, but no standard mandates using a hand surgeon for partial extensor tendon lacerations, and many EPs handle simple ones on their own.

Sagacious clinicians pursue a careful course that often involves at least consultation with a hand surgeon who agrees to follow up or manage any rehabilitation. Unfortunately, hand surgeons don't troll the ED for homeless guys who cut a tendon in a drunken bar fight. Some surgeons won't even take ED call anymore, or consider any tendon injury care initiated in the ED. These are local political issues that must be sorted out.

Overlooking an extensor tendon injury is relatively easy when one is juggling other patients. Suppress the urge to relegate the entire care of even a seemingly simple hand laceration to the medical student or intern. A cursory examination or a truncated explanation to the patient about potential problems and the need for timely follow-up are common pitfalls that even gray-haired professors still make. Approach each hand laceration with the notion that something is wrong until proven otherwise. Physician hubris, inattention to detail, a hurried evaluation, and a less-than-ideal patient are bad combinations.

This is a terrific summary of extensor tendon injuries. Although the novice may think the extensor tendon is a simple structure, not so, say these authors. The anatomy and function is actually more intricate and complex than the flexor system. Interconnecting components and the extensor apparatus link a variety of systems and tendons. Note the connection and sharing of the extensor apparatus with an adjacent finger, making even complete tendon rupture more difficult to appreciate on a functional basis. Unlike flexor tendons, extensor tendons are superficial, easily lacerated, and almost entirely extrasynovial.

Contrary to belief, extensor tendons do represent a significant challenge in treatment and rehabilitation, and significant efforts are required to attain complete function following injury. Rehabilitating an extensor tendon is not a simple task.

Injuries to tendons over the dorsal metacarpophalangeal (MCP) joint, also termed fight bites, are omnipresent. Despite adamant patient denial and without good evidence, classic MCP lacerations should always be considered to be caused by a human bite. With a closed fist injury, the actual tendon insult may be proximal to the skin laceration when the palm is flat on the examining table. Viewing the laceration in extension is the only way to see a now-retracted tendon injury that occurred while throwing a fist because the portion of the tendon that now appears under the laceration will look intact. An infected joint is a well known complication. Primary repair of extensor tendons in a human bite is not a reasonable option.

Partial tendon lacerations may be difficult to diagnose by testing extensor function. Many of the extending forces are transmitted from adjacent and interconnected extensor mechanisms, requiring direct inspection of the tendon to rule out injury. The ligamentous and fascial interconnections are known as the juncturae tendini.

This extensive article details many extensor tendon injuries that I will not cover. Read the original article for a erudite discussion as well as informative diagrams showing anatomic detail. (Also see J Emerg Med 1986;4[3]:217.)

Comment: Extensor tendon lacerations are not always portrayed as significant injuries, taking a backseat to more exotic flexor tendon discussions, but lacerated extensor tendons should not be taken lightly. Special attention is required to prevent long-term sequelae. Assuming that function is evaluated, few clinicians would miss a completely ruptured flexor tendon. Unfortunately, the fascial and ligamentous interconnections on the dorsum of the hand make many extensor tendon injuries quite subtle. They can fool even the most experienced clinician.

This patient claimed he cut his hand on a machine at work, likely giving this history so his ED care would be covered by worker's compensation insurance. Of course, any EP knows this is a human bite that should not be sutured and that requires diligent wound care. This laceration should be examined for tendon injury, joint penetration, or foreign body (piece of tooth).

This patient claimed he cut his hand on a machine at work, likely giving this history so his ED care would be covered by worker's compensation insurance. Of course, any EP knows this is a human bite that should not be sutured and that requires diligent wound care. This laceration should be examined for tendon injury, joint penetration, or foreign body (piece of tooth).

A deep laceration in this area simply has to involve the extensor tendon. The pathology is obvious simply by noting the posture of the hand with the inability to extend the index finger. A complete tendon laceration was readily found. This likely requires the expertise of a hand surgeon, but the consultant does not have to come to the ED for this one. The wound was thoroughly irrigated, the skin sutured, a splint applied, and antibiotics prescribed (probably not needed, but few would eschew the antimicrobial). Primary tendon repair was accomplished five days later with a good result.

A deep laceration in this area simply has to involve the extensor tendon. The pathology is obvious simply by noting the posture of the hand with the inability to extend the index finger. A complete tendon laceration was readily found. This likely requires the expertise of a hand surgeon, but the consultant does not have to come to the ED for this one. The wound was thoroughly irrigated, the skin sutured, a splint applied, and antibiotics prescribed (probably not needed, but few would eschew the antimicrobial). Primary tendon repair was accomplished five days later with a good result.

No clinician would disagree that a history of the mechanism of injury and a complete physical exam are paramount to proper medical care, but look at the last simple hand laceration you treated to see if your charting was up to snuff. Assume that a patient with a seemingly innocuous laceration repaired by the medical student demonstrates complete tendon rupture on suture removal. Critically read the chart to see if your documentation demonstrated prudent evaluation and treatment, a narrative that would convince the patient that you made an effort at 2 a.m. to evaluate and explain the possible foibles of the injury.

The vast majority of clinicians give cursory attention to etiology. “Hand lac” is hardly an adequate history. I almost never see timing of the incident or the patient's own words quoting their perception of sensation, function, or possibility of foreign body. It's almost unheard of to encounter documentation of things such as the attitude of the hand prior to evaluation or the results of testing against resistance. See if you documented response to light touch and two-point discrimination, and evaluate your follow-up instructions and splinting and bandaging techniques.

Carefully note the positive and negatives, best accomplished with a templated charting system or a electronic macro. Often the negatives are more helpful than the positives. The standard phrase, “NVT intact,” does little to convince anybody that a thorough examination was performed. Tendon evaluation cannot occur in a vacuum that ignores nerve, vascular, and bony injuries.

No agreed-upon standard is required of your chart documentation unless there are problems; then it's your word against the patient and his expert. Be especially wary of lacerations suspicious for a human bite. This injury often presents on a Monday because crafty patients have learned that if they claim an injury at work, worker's comp will foot the bill. If a patient denies an obvious human bite, note this in bold letters on the chart, and state you asked that specific question (“denies human bite x 3”). If the injury is classic, treat as a human bite, regardless of history.

If a patient can't tell you whether the hand was flexed or opened, such information should be documented. At least you asked. Document if the patient thinks this is a serious hand injury, if the hand and fingers work, and if there is a possibility of a retained foreign body or broken bone. You would be surprised how many patients with missed foreign bodies or ruptured tendons state that the doctor never asked such questions, or they specifically told the doctor that they thought glass was in the wound, or the finger did not work quite right. Two years later, they claim the clinician ignored their specific complaint or simply failed to look. Unless pertinent negatives are charted, it's difficult to counter patient accusations that the evaluation was lax. Maybe you spent an hour, but two lines on the chart give the impression of a cursory encounter.

Simple lacerations do not require a radiograph. A human bite can fracture a metacarpal, penetrate the joint, or leave a tooth in the wound. Occasionally you will see air in the joint space. Almost all glass is visible on plain x-rays, but small pieces will be missed. For the patient who fell on an outstretched hand in a field, stuck his hand in the garbage can, or punched out a window, a 2-3 view radiograph is mandatory unless the laceration is obviously superficial. Plain radiographs have a high sensitivity for detecting most foreign bodies of the hand. (Ann Emerg Med 1996;28[1]:7.) Don't ignore that little white speck.

I urge clinicians who naïvely believe they can accurately intuit a foreign body by history or find foreign bodies in wounds by a careful examination to read an article by Steele et al. (Am J Emerg Med 1998;16[7]:627.) Retained glass was found by x-ray in 16 of 146 wounds that were deemed foreign body-free by the patient's history and perception. Eight foreign bodies were seen on x-ray in 165 wounds when the physician's wound exploration was negative.

Examine each finger individually; the overlap and interconnections of the extensor tendon apparatus allow seemingly normal motion when a major tendon is completely transected. Many patients who have painful injuries are reluctant to move digits, but usually some motion can be detected. Motion limited by pain can indicate a normal tendon or one that is 90 percent lacerated. Never conclude that a patient who says his finger won't work is in too much pain to move it, too drunk, or just being uncooperative.

Even a fully lacerated extensor tendon may give the impression of normal function because of the interlocking juncturae tendinum. In this illustration, the extensor tendon of the middle finger is completely lacerated, yet the finger will extend, albeit weakly.

Even a fully lacerated extensor tendon may give the impression of normal function because of the interlocking juncturae tendinum. In this illustration, the extensor tendon of the middle finger is completely lacerated, yet the finger will extend, albeit weakly.

If a finger doesn't move, regardless of the apparent severity of the injury, assume a complete tendon laceration. With a little bit of coaxing, even a painful injury can demonstrate some movement. Even if a tendon is 80 percent lacerated, it will provide some function, and many will appear surprisingly normal. If tested against resistance, however, weakness is readily apparent. It's OK to administer analgesics if the patient is in so much pain you cannot examine tendon function.

In most cases, a partially lacerated superficial extensor tendon will not escape visual detection. You may have to extend the skin laceration a bit, a difficult intervention for a timid resident but standard for the seasoned veteran. A tourniquet and local lidocaine help. The most common clinical error is to assume that full range of motion guarantees an unscathed tendon. Partial injuries may heal and never be diagnosed, but many progress to complete rupture, complicating repair or delaying definitive intervention.

Some subtle clues cue the presence of a partial tendon laceration, the first being the patient's description of hand and finger activity. Ask if everything works normally, and listen carefully to the answer. Merely asking the patient to extend the finger while you watch can be misleading. One red flag is weak extension against resistance, a rather vague concept on your first exam of a painful injury. If you don't test a tendon against resistance, you will not appreciate this subtle abnormality. A completely intact tendon is strong, and should not give way with an opposite force, and is not hampered merely by a skin laceration. If the patient demonstrates ability to move the finger -partially, it may be too painful. But if it is weak, always assume a partial tendon injury unless your own eyes tell you differently.

Another clue is pain in the wound itself with tendon movement. Cut edges of tendons irritate the delicate tissues, and don't glide well. Look at the resting posture of the hand. The body just knows that a partially lacerated tendon should not be stressed. Finally, neurologic or vascular deficits may signal an injury deep or extensive enough to raise suspicion of collateral tendon damage.

The takeaway message is that it is almost impossible to lacerate the dorsum of the hand and not at least partially injure an extensor tendon. This concept is one that you should learn on your first day in the ED and impart to every resident, medical student, PA, and NP.

Most articles written by hand surgeons conclude that EPs should immediately refer all questionable extensor tendon problems to a hand surgeon. This sounds good on paper, but I have yet to meet a hand surgeon who will comply with his own mandate. Such a response is rarely required. Certainly a hand surgeon cannot sober up an intoxicated patient or cajole him into cooperation, and an EP can certainly test motor and sensory function as well as a specialist.

The near-universal answer from hand surgeons about a questionable tendon finding is: “Clean the wound, close it loosely, splint it, prescribe antibiotics, and send him to the office.” It's rarely answered by: “I will be there in an hour to repeat your examination.” Local customs vary, but most surgeons will not routinely take patients from the ED to the OR to explore or repair tendons. Many delay this for a few days until swelling, infection, and bleeding is controlled. Good results are obtained even after five to seven days.

No special follow-up is required for dorsal hand lacerations where tendons can be visualized throughout the full range of motion, and a partial tendon injury can be absolutely excluded. Standard wound care is appropriate. No data support routine use of prophylactic antibiotics for penetrating hand trauma, but many clinicians prescribe them. Unlike flexor tendons, one need not worry about inoculation of a tendon sheath with extensor tendons; they don't have one.

I often hear housestaff pontificate that all hand lacerations require antibiotics. That's incorrect and a bad axiom to reiterate, even if the hand surgeon agrees. No standard mandates routine antibiotics for any soft tissue laceration, and not a single study has proven them useful. I have yet to see the study where diabetics do better with antibiotics for common lacerations. Antibiotics are not a substitute for proper wound irrigation, removal of foreign bodies, or immobilization.

Patients must be cooperative, alert, and otherwise intelligent enough to participate in the examination. Unfortunately, such traits are not prerequisites for an ED visit. One is often faced with situations that make proper textbook evaluation impossible. Occasionally a few hours of sobering up, a shot of morphine, or a family member can facilitate an examination, but it's unrealistic to believe you will always get the information you want on the first visit.

My approach to the uncooperative patient who has an incomplete or equivocal examination is straightforward. Simply assume there is a tendon laceration, foreign body, or something else bad, and institute standard guidelines for that badness. Document that there is likely a foreign body or tendon laceration that cannot be fully addressed in the ED, and provide a reasonable alternative. An AMA form might help but not always for the drunk/drugged, so document a normal mental status, albeit it an uncooperative or hostile one. If you are wrong about the prognosticated pathology, nobody cares that you were overly cautious. If correct, you look like a pro. I caution again to believe a patient who says he can't move a finger. Complete absence of movement is rarely malingering or noncompliance to the exam.

Partial extensor tendon injuries, even significant ones, are commonly handled with splinting and without surgical repair. But there is controversy about the best course of action for known partial tendon lacerations. (J Hand Surg Am 2001;26[5]:821; Plast Reconstr Surg 1977;59[2]:231; J Biomech Eng 2000;122[6]:604; J Bone Joint Surg Am 2002;84-A[6]:1006.) I get a different answer each time I ask, often from the same hand surgeon. All sorts of trimming procedures, splinting, and physical therapy protocols have been advocated.

Once healed, sutured tendons may not be as strong than those allowed to heal without surgery. Most surgeons will not suture a tendon that is cut 50 percent or less. Others allow even greater partial lacerations to go unsutured. Some evidence suggests that suturing a partial tendon laceration provides a worse outcome than conservative splinting and physical therapy. Of course, one has to make the diagnosis of a partial tendon laceration in the first place before therapy is set.

Most hand surgeons prefer to repair complete extensor tendon lacerations three to seven days after injury, which fits nicely with a three- to five-day follow-up after the ED visit.

Complete lacerations are best left to a hand surgeon because of follow-up and long-term issues, but there is no law against an EP taking this one on. Partial lacerations can be repaired with 4-0/5-0 vicryl and splinting for four weeks. Placing a few interrupted sutures in an extensor tendon is not rocket science.

Completely lacerated tendons are repaired with nonabsorbable material (usually nylon) by fancy stitches named after old hand surgeons. A delayed primary repair can be performed up to 10 days after injury with reasonable results. Secondary repair of an extensor tendon can be performed within two to four weeks post-injury. Generally the results are about equal with immediate, delayed, and early secondary repair, but repair of tendons after three or four weeks often yields poor results. A missed tendon injury that progresses from partial to complete rupture by the time of suture removal is generally amenable to a final result similar to expected had the diagnosis been made in the ED. But this is clearly an inopportune and embarrassing time to make the diagnosis.

This intoxicated patient was in a knife fight in a bar, was uncooperative in the ED, and refused a proper exam or wound exploration. Function seemed intact, but the laceration's position and depth alone prognosticated an extensor tendon injury. The patient missed a follow-up visit, and finally surfaced for suture removal four weeks later, and the complete tendon rupture was obvious. A less-than-ideal result will follow, so be squeaky clean on your chart documentation of this injury and any ED encounter.

This intoxicated patient was in a knife fight in a bar, was uncooperative in the ED, and refused a proper exam or wound exploration. Function seemed intact, but the laceration's position and depth alone prognosticated an extensor tendon injury. The patient missed a follow-up visit, and finally surfaced for suture removal four weeks later, and the complete tendon rupture was obvious. A less-than-ideal result will follow, so be squeaky clean on your chart documentation of this injury and any ED encounter.

It's difficult to be 100 percent normal after injuring delicate tendons in the hand, so tread carefully. Patients who are noncompliant, have financial problems, or lack social support or the wherewithal to follow up are a nightmare for all. Everything can be done correctly and follow-up carefully spelled out, yet the patient and the hand surgeon never meet within the appropriate timeframe to get the best possible result. Unfortunately, the EP is often blamed for the poor outcome, regardless of gargantuan (but often undocumented) time and effort during the initial visit. The most common criticisms are that the EP missed an injury, failed to get proper consultation, or never informed that patient of the important issues. This is where proper and detailed charting saves the day. When in doubt, assume the worst. Routine splinting of all potential partial injuries can never be faulted. Treatment, even with an incorrect diagnosis with treatment that erred on the side of caution, should be the clinician's mantra.

Dr. Roberts

Dr. Roberts

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Dr. Roberts: I just read your article, “Tendon Injuries of the Hand: Flexor Tendon.” (EMN 2011;33[11]:26; http://bit.ly/Flexor.) It was very informative, eye-opening, and practice-changing. (I will probably make a templated chart as you recommended.) I am writing hoping you can clear up some confusion. Numerous times throughout the article you stress the need to document that the patient does not feel like it is a serious injury and there is no foreign body or nerve injury. You state that this is something important to document and could prevent litigation, but later in the article you mention to read the article by Steele et al (Am J Emerg Med 1998;16[7]:627), which states that 16 of 146 patients who thought they had no foreign body actually did. You recommend we document that the patient doesn't feel there is a foreign body, but you also state, per Dr. Steele's article, that it doesn't matter based on imaging. Please clarify. Thank you.— Scott Goldstein, DO, Philadelphia

Dr. Roberts responds: Although this issue may seem confusing, my reasoning, which I largely made up based on the unfortunate experience of colleagues who missed foreign bodies or other injuries that were found on follow-up, is the following: The chart should document on the first visit that you at least knew about the basic concept of foreign bodies in lacerations and the entity of a partial tendon laceration. Show that you gave the patient a chance to impart his thoughts about the pathology for his injury. Importantly, such verbiage confirms that you actually asked the appropriate questions and listened to the answer. You and the patient will certainly be wrong sometimes, but at least you asked, and it was a joint effort to ferret out the truth.

I have encountered cases where the patient returns with a foreign body, nerve injury, or tendon laceration, and claims he told the doctor there might be glass in the cut, the fingers were numb, or a finger could not flex, but now claims the doctor totally ignored that. Your initial chart makes you look like a dope because it does not demonstrate enough for anyone to disbelieve the patient's litigation-driven version.

If such specific issues were never addressed in writing, it's difficult to convince anyone how thorough you were. When you chart as I suggest, at least you memorialized the details of the encounter in real time. Do not, however, put anything in writing that you did not do. This is a real danger of macros so know what the macro says and follow it precisely. Better to say, “There may be a partial tendon injury,” than to conjure up the hubris to say, “I am the doctor, and all is well.”

Same goes for many ED encounters. When you send anyone home with vague abdominal pain, the chart should reflect that you know people have appendixes and can get appendicitis, but that you specifically looked for appendicitis in an appropriate manner, and there was “no evidence of appendicitis” when you sent them home. Good charting equates good medicine.

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